Thrombin-activatable fibrinolysis inhibitor (TAFI) antigen and activity assay in patients with primary hypothyroidism.

Abstract

Hypothyroidism causes a tendency for cardiovascular diseases. It was recently shown that thrombin-activatable fibrinolysis inhibitor (TAFI) attenuates fibrinolysis and also fibrin-plasminogen interaction by the removal of lysine and arginine residues from fibrin monomers. The aim of this study was to determine the effects of overt hypothyroidism on the levels of TAFI antigen (TAFI Ag) and TAFI activity (TAFIa). Thirty-one overt primary hypothyroid patients and age- and gender-matched 25 healthy controls were enrolled in the study. Patients were treated with L-thyroxine after the collection of blood samples. Thyroid functions were reevaluated following the achievement of euthyroid status. Thrombin-activatable fibrinolysis inhibitor Ag, tissue plasminogen activator (t-PA), and plasminogen activator inhibitor 1 (PAI-1) levels were measured with the enzyme-linked immunosorbent assay (ELISA). Thrombin-activatable fibrinolysis inhibitor activity was assessed with the chromogenic assay. Thrombin-activatable fibrinolysis inhibitor Ag (1.63% + or - 0.42% vs 1.32% + or - 0.36%, P < .01) and TAFIa (14.2 + or - 4.12 vs 11.6 + or - 3.49 microg/mL, P < .05) levels were elevated in hypothyroid patient compared to controls. Plasminogen activator inhibitor 1 and t-PA levels were not significantly different between both groups. In hypothyroid patients, TAFI Ag levels were correlated with free T(4) (r = -.373, P < .05) and thyroid-stimulating hormone (TSH) levels (r = .748, P < .001). Regression analysis showed that TSH levels were predictors of TAFI Ag levels (P < .001, beta =.671, 95% confidence interval [CI]: 0.008-0.017). Following L-thyroxine treatment, TAFI Ag (1.63% + or - 0.42%, 1.34% + or - 0.33%, P < .05) and TAFIa (14.2 + or - 4.12 microg/mL, 12.0 + or - 2.77 microg/mL, P < .05) levels were significantly decreased, but t-PA and PAI-1 levels remained unchanged. This results point out that the fibrinolytic activity was decreased in hypothyroid patients, and therefore the achievement of euthyroid status is important in ameliorating the increased risk of cardiovascular disease.

• Authors: Nilay Ermantas, Sibel Guldiken, Muzaffer Demir, Armagan Tugrul
• Journal: Clinical and applied thrombosis/hemostasis : official journal of the International Academy of Clinical and Applied Thrombosis/Hemostasis (Clin Appl Thromb Hemost) Vol. 16 Issue 5 Pg. 568-73 (Oct 2010) ISSN: 1938-2723 [Electronic] United States
• PMID: 19959491 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens
• Plasminogen Activator Inhibitor 1
• Carboxypeptidase B2
• Tissue Plasminogen Activator
• Thyroxine

Topics

• Antigens (blood)
• Carboxypeptidase B2 (blood, immunology)
• Case-Control Studies
• Female
• Humans
• Hypothyroidism (blood, drug therapy, enzymology, immunology)
• Male
• Middle Aged
• Plasminogen Activator Inhibitor 1 (metabolism)
• Thyroid Function Tests
• Thyroxine (therapeutic use)
• Tissue Plasminogen Activator (blood)